Known as "charge axe" in Japan. A type of weapon introduced to the Monster Hunter series as of Monster Hunter 4. The weapon comes in two parts - a sword and a shield - which can be either used separately, or combined to form a large axe.
The strategy of using the weapon's two forms generally revolves around using the sword to charge energy and the shield for defense, then using the energy by switching to axe mode to deliver large amounts of damage.